Commutator for dynamo-electric machines.



T. s; SCOTT. Y GOMMUTATOR FOR DYNAMO'ELBGTRIC MACHINES. APPLICATIONFILED DEU. I4, l908.`

Y Patented Dot. 14, 1913.

WITNESSES:

d IENTO 2PZ-Q ATTORNEY UNITED sTETEs PATENT oEETcE.

THOMAS S. SCOTT, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSEELECTRIC & MANUFACTURING COMIANY, A CORPORATION OF PENNSYLVANIA.

COMIVIUTATOR FOR DYNAMIC-ELECTRIC MACHINES.

Specification of Letters Patent.

Patented Oct. 14, 1 91.3.

Application filed December 14, 1908. Serial No. 467,463,

To L7/Z tolto/m it may concern.'

Be it known that I, Tnoinxs S. SCOTT, a citizen of the United States,and a resident or" Pittsburgh, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in Commutatorsfor Dynamo-Electric lilachines, of which the following is aspecification.

My invention relates to commutatore for dynamo-electric machines, and ithas for its object to 'provide a simple device of this character whichshall be specially adapted for use with machinesl to be operated atrelatively high speeds, by steam turbines, or otherwise.

1Vhen large machines of the commutator type are operated athigh speeds,the devices usually employed for clamping the commutator bars inposition are inadequate, by reason of the very large centrifugal forceto which the comniutators are subjected. AC- cording to my presentinvention, I provide a plurality of rings which severally comprise alarge number of turns of steel band Wire and are located either on thesurface of the commutator cylinder or in annular grooves in said surfacefor the purpose of holding the bars or segments securely 1n po sition,the rings being suitably insulated from the commutator cylinder to avoidshort-circuiting the commutator bars.

Figure 1 of the accompanying drawings is a longitudinal section. ofone-half of a com' mutator cylinder constructed in accordance with myinvention, and Fig. 2 is an en- .larged sectional view ot one of thebinding rings shown in Fig. 1. Fig. E is a View similar'to Fig. 1 butillustrating a modification of my invention and Fig. 4.- is a sectionalView of one of the binding rings sloivn in Fig. 3.

Referring to Figs. 1 and 2 of the draw-- ings, the mattei illustratedcomprises an i armature of a dynamo-electric machine having amagnctizable core membernl, end rings 2, a supporting frame or spider 3and ai connnutator cylinder 4. The commutator cylinder et comprises acylindrical projec tion 5 of the spider 3, a plurality of bars orsegments 6 which are mounted on the surface of the cylinder 5 and areseparated therefrom by a bushing I of insulating material. Each ot thebars-G is provided. with a neck or connector which extends radially outvard from its inner end and with a notch 9 at its outer end. vVhen thebars are assembled, the notches 9 forni a cylindrical projection 91 atthe outer end of the commutator cylinder, the diameter of which issomewhat lessy than that of the contact. surface of the cylinder'. Thebars (3 are held in position. by rings 10 and 11 which encircle thecylinder, one being disposed adjacent to the necks 8 and the other beinglocated on the cylindrical projection 9a. The rings 10 and 11 areseparated from the bars 6 by stripslQ of insulating material and' eachof them comprises a metal ring 13 ot' U-shape in cross section, whichmay be split transversely or composed of a plurality of segments, alarge number of turns or convolutions l'of steel band Wire and asuperposed metal ring 15, which may also be either split or of segmentalstructure, the edges of the ring 13 being bent inward tohold the ring 15in position. The splitting of either or both oi' the rings 13 and 15 orthe dividing of them, or either of them, into a plurality of segments isa matter of expediency in manufacturing and assembling, and neitherstructure is presented as a feature of patentable novelty. After therings 10 and 11 are formed, as above indicated, each of them is providedWith a Wrapping 1G of insulating material which is overlapped on theouter cylindrical surface 'of the ring and is held in position by alayer of convolutions 1.7 of twine or cord, a linal covering 18 being`Wrapped around the circuinterence of the ring on top of the cord andheld in position by sewing to the insulating Wrapping 16. lVhen therings 10 and 1l are completed, they may be handled in the saine Way as asolid metal ring so that it it is desired` to dismem'ber thecoininutator, for any reason, the rings may be heated until they expandsuiiciently to be readily removed from the commutator cylinder. Therings 10 and 11 are preferably constructed by Winding the necessaryAconvoll'itious of bandwire upon the U-shaped rings 18 after the latterand the Wrappings 1G have been placed in position upon the commutatorcylinder. The sides of the metal rings 13 are preferably slotted to formfingers 132L which may be easily bent over the edges of the ring 15.

)teterring to Figs. 3 and 4; of the drawings, commutator bars orsegments 19 are mounted on a bushing 20 from which they are separated bymeans of insulating rings 2l. The bushing 20 is provided with an.enlargement 22 having a truste-conical outer surface, and a ring 28,having a similar ouixfisurface, is mounted on the opposite en d of thebushing. The position of the ring 23 may be varied by means of anadjusting nut 24 which is screwed upon the outer end of the bushing 20.The inner edges of the bars or segments '19 are adapted to fit againstthe frusto-eonical surface provided by the enlargement 22 and the ring23 and the segments are of Wedge shape in cross section so that they maybe readily assembled to 'form a, cylindrical eonnnutator structure, inthe usual manner. The commutator cylinder is provided with a pluralityof annular grooves 25 which are intended to receive suiiicient turns 26of steel band wire to hold the bars in position. The walls of thegrooves are first insulated by means of rings 27 of U-shape in crosssection. A similar ring or casing 28 of sheet brass is fitted into theinsulating ring 27, the band Wire being disposed Within the brassVeasing which is intended to prevent injury to the insulation by theband Wire. Afterdhe band Wire is' Wound upon the brass rings, thecas-ing is closed by bending tlle/ edges of said rings over a coverstrip 29, an insulating strip BO being held in position by any suitablemeans such as a layer of ttt'ine. 3l. Bylproperly designing the grooves25 to receive the necessary nana wire and insulation, the surface of theinsulating twine may be substantially flush with the cylindrical surfaceoithe commutator. It will, of course, be understood that the parts 27,28, S29 and 30 will be severally split transversely or composed of aplurality of segments in order that they may be as sembled in thegrooves 25.

I desire that structural modifications which do not depart from thespirit of my invention shall be included Within its scope.

l Claim as my invention:

l. A commutator comprising a plurality of bars or segments and aplurality of clamping rings therefor, each of Which compriseseonvolutions of Wire, a sheet nie-tal easing for the Wire and aninsulating casing for the sheet metal.,

2. A commutator compris-ing a cylindrical bushing, a plurality ot barsor segments mounted thereon and insulated therefrom THS. S. SCOTT,l'Vitnesses F. C. HALL, Binner Hines.

